Lead-free and cadmium-free glass compositions are generally used to form glass frits which are, in turn, used to formulate glass enamel compositions. These glass/glass ceramic enamel compositions are useful for forming decorative coatings for glassware, chinaware, architectural glass and the like.
One particular application for lead and cadmium free glass enamel compositions that fuse at low temperatures is the formation of opaque, dark colored enamel bands on sections of automotive glass, such as windshields and side and rear windows. Automotive manufacturers have found that the appearance of a section of glass is greatly enhanced by applying a relatively narrow, opaque, dark colored enamel band around one or more edges of a section of glass on the inner surface thereof. This band may vary somewhere about 2.5 cm to about 15 cm in width. In addition to imparting an aesthetically appealing appearance to the section of the glass, these opaque, colored enamel bands preferably block the transmission of sunlight and thereby prevent the degradation of underlying adhesive by ultraviolet radiation. Moreover, these opaque colored enamel bands preferably conceal a section of the silver-containing buss bars and wiring connections of rear glass defrosting systems from view from the outside of the vehicle.
In general, these enamel compositions contain a glass frit, a colorant and an organic vehicle. They are applied to a desired substrate and subsequently fired to burn off the organic vehicle and fuse the frit, thus bonding the enamel coating to the substrate.